Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEEE International Semiconductor Laser Conference (ISLC)

Searching for Lasing Threshold in a Thresholdless Laser

Chi‐Wai Chow, F. Jahnke, Christopher Gies

Published Sep 1, 2014• 1 citation
Publisher

Abstract

A quantum-optical model is applied to address the question of criteria for lasing in a threshold less laser where the intensity jump, customarily used to indicate transition to lasing, is missing.
DOI
10.1109/islc.2014.242

Related papers

Finding threshold in a thresholdless laser

Chi‐Wai Chow, F. Jahnke, Christopher Gies

Cavity-quantum-electrodynamics is applied to address the questions of criteria and nature of lasing in devices where the intensity jump customarily used to indicate lasing threshold is missing.

IEEE Photonics Conference•Dec 1, 2014•0 citations

From the ordinary threshold regime to ideal thresholdless lasing

S. M. Dutra, Jorrit Visser, Gerard Nienhuis +1 more

Springer eBooks•Jan 1, 2003•1 citation

First Principle Study of Nanolasers: Photon Statistics and Laser Threshold

Chi‐Wai Chow, F. Jahnke, Christopher Gies

A semiconductor quantum-optical theory is developed and applied to address questions involving thresholdless lasing and increasing single-photon production rate. Excitation dependences of intensity, coherence time, photon autocorrelation function and carrier spectral hole burning are described.

Asia Communications and Photonics Conference•Jan 1, 2014•0 citations

Laser intensity fluctuations when the photon number at threshold is small

Wallace Arden Smith

Optics Communications•Nov 1, 1974•3 citations

Thresholdless coherence in a superradiant laser

Seung-Hoon Oh, Jinuk Kim, Junseo Ha +2 more

Lasing threshold in the conventional lasers is the minimum input power required to initiate laser oscillation. It has been widely accepted that the conventional laser threshold occurring around a unity intracavity photon number can be eliminated in the input-output curve by making the so-called β parameter approach unity. The recent experiments, however, have revealed that even in this case the photon statistics still undergo a transition from coherent to thermal statistics when the intracavity mean photon number is decreased below unity. Since the coherent output is only available above the diminished threshold, the long-sought promise of thresholdless lasers to produce always coherent light has become questionable. Here, we present an always-coherent thresholdless laser based on superradiance by two-level atoms in a quantum superposition state with the same phase traversing a high-Q cavity. Superradiant lasing was observed without the conventional lasing threshold around the unity photon number and the photon statistics remained near coherent even below it. The coherence was improved by reducing the coupling constant as well as the excited-state amplitude in the superposition state. Our results pave a way toward always-coherent thresholdless lasers with more practical media such as quantum dots, nitrogen-vacancy centers and doped ions in crystals.

Light Science & Applications•Sep 5, 2024•6 citations

Thresholdless dressed-atom laser in a photonic band-gap material

Gao‐xiang Li, Min Luo, Z. Ficek

We demonstrate the capability of complete thresholdless lasing operation between dressed states of a two-level atom located inside a microscopic cavity engineered in a photonic band-gap material. We distinguish between threshold and thresholdless behaviors by analyzing Mandel's $Q$ parameter for the cavity field. We find that the threshold behavior depends on whether the spontaneous emission is or is not present on the lasing transition. In the presence of the spontaneous emission, the mean photon number of the cavity field exhibits threshold behavior, indicating that the system may operate as an ordinary laser. When the spontaneous emission is eliminated on the lasing transition, no threshold is observed for all values of the pumping rate, indicating the system becomes a thresholdless laser. Moreover, we find that, under a thresholdless operation, the mean photon number can increase nonlinearly with the pumping rate, and this process is accompanied by a sub-Poissonian statistics of the field. This suggests that the nonclassical statistics can be used to distinguish a nonlinear operation of the dressed-atom laser.

arXiv:0807.4773•Physical Review A•May 26, 2009•9 citations
Lasing threshold in the conventional lasers is the minimum input power required to initiate laser oscillation. It has been widely accepted that the conventional laser threshold occurring around a unity intracavity photon number can be eliminated in the input-output curve by making the so-called β parameter approach unity. The recent experiments, however, have revealed that even in this case the photon statistics still undergo a transition from coherent to thermal statistics when the intracavity mean photon number is decreased below unity. Since the coherent output is only available above the diminished threshold, the long-sought promise of thresholdless lasers to produce always coherent light has become questionable. Here, we present an always-coherent thresholdless laser based on superradiance by two-level atoms in a quantum superposition state with the same phase traversing a high-Q cavity. Superradiant lasing was observed without the conventional lasing threshold around the unity photon number and the photon statistics remained near coherent even below it. The coherence was improved by reducing the coupling constant as well as the excited-state amplitude in the superposition state. Our results pave a way toward always-coherent thresholdless lasers with more practical media such as quantum dots, nitrogen-vacancy centers and doped ions in crystals.
We demonstrate the capability of complete thresholdless lasing operation between dressed states of a two-level atom located inside a microscopic cavity engineered in a photonic band-gap material. We distinguish between threshold and thresholdless behaviors by analyzing Mandel's QQQ parameter for the cavity field. We find that the threshold behavior depends on whether the spontaneous emission is or is not present on the lasing transition. In the presence of the spontaneous emission, the mean photon number of the cavity field exhibits threshold behavior, indicating that the system may operate as an ordinary laser. When the spontaneous emission is eliminated on the lasing transition, no threshold is observed for all values of the pumping rate, indicating the system becomes a thresholdless laser. Moreover, we find that, under a thresholdless operation, the mean photon number can increase nonlinearly with the pumping rate, and this process is accompanied by a sub-Poissonian statistics of the field. This suggests that the nonclassical statistics can be used to distinguish a nonlinear operation of the dressed-atom laser.